Spreading exponents: dynamics of trisiloxane wetting of hydrophobic surfaces

J. Radulovic*, K. Sefiane, M. E. R. Shanahan

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference contribution


    The excellent spreading and wetting behaviour of superspreader solutions has been known and extensively studied over recent years. However, explanations for spreading dynamics and accompanying mathematical models have not yet proved completely successful. Many attempts have been made to quantify the spreading exponents, but none of the models so far was able successfully to describe the whole wetting process of trisiloxane solutions, especially on hydrophobic surfaces. We have investigated the partial wetting of Silwet L-77® superspreader solutions of high concentrations (well above CMC) on polymer coated substrates of varying hydrophobicity. Results obtained can be explained in terms of the Marangoni effect as the major driving force for trisiloxane enhanced spreading. A simple theory, which involves surface tension gradients governing the spreading process, was developed in order to explain the specific evolution of the drop radius and consequent decrease in the contact angle. The proposed model was found to be in excellent agreement with the experimental results. Determined equation coefficients were shown to be dependent on both surfactant concentration and the hydrophobicity of the substrate.

    Original languageEnglish
    Title of host publicationDefects and Diffusion in Semiconductors XII
    PublisherTrans Tech Publications Ltd
    Number of pages7
    ISBN (Print)3908451876, 9783908451877
    Publication statusPublished - 1 Jan 2010


    • Hydrophobicity
    • Surfactant
    • Trisiloxane
    • Wetting dynamics


    Dive into the research topics of 'Spreading exponents: dynamics of trisiloxane wetting of hydrophobic surfaces'. Together they form a unique fingerprint.

    Cite this